Welfare Aspects of the Production of Foie Gras in Ducks and Geese - Report of the Scientific Committee on Animal Health and Animal Welfare Adopted ...
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Welfare Aspects of the Production of Foie Gras
in Ducks and Geese
Report of the
Scientific Committee on Animal Health and Animal Welfare
Adopted 16 December 1998
Contents of the Report
Page
INTRODUCTION......................................................................................................................................... 1
1 WELFARE DEFINITIONS AND MEASUREMENT ........................................................................ 2
1.1 DEFINITIONS OF WELFARE ...................................................................................................................... 2
1.2 ASSESSMENT OF WELFARE ..................................................................................................................... 3
1.3 COMBINING RESULTS FROM DIFFERENT INDICATORS.............................................................................. 11
1.4 SUMMARY ........................................................................................................................................... 12
2 THE ORIGINS AND DISTRIBUTION OF FOIE GRAS PRODUCTION ..................................... 14
2.1 THE PRODUCTS .................................................................................................................................... 14
2.2 ORIGINS AND SPECIES .......................................................................................................................... 15
2.3 PRODUCTION IN FRANCE ...................................................................................................................... 16
2.4 PRODUCTION IN BELGIUM .................................................................................................................... 17
2.5 PRODUCTION IN SPAIN ......................................................................................................................... 18
3 THE PRACTICE OF REARING AND FORCE FEEDING ........................................................... 19
3.1 MANAGEMENT BEFORE THE FORCE FEEDING PERIOD .............................................................................. 19
3.2 MANAGEMENT DURING THE FORCE FEEDING PERIOD.............................................................................. 19
3.3 HOUSING OF DUCKS AND GEESE DURING THE FORCE FEEDING PERIOD...................................................... 21
4 NORMAL BEHAVIOUR AND OTHER FUNCTIONING OF GEESE AND DUCKS
RELEVANT TO FORCE FEEDING ................................................................................................ 24
4.1 THE NATURAL BEHAVIOUR OF GEESE, MUSCOVY DUCKS, DOMESTIC DUCKS AND THEIR HYBRIDS .............. 24
4.2 OCCASIONS FOR FOOD STORAGE IN BIRDS ............................................................................................ 26
4.3 THE NEEDS OF GEESE AND DUCKS IN RELATION TO FEEDING AND POSSIBLE CONSEQUENCES OF FORCE
FEEDING........................................................................................................................................... 27
4.4 FEEDING BEHAVIOUR AND ACTIVITY OF DUCKS AND GEESE..................................................................... 29
5 CONSEQUENCES OF FORCE FEEDING: WELFARE INDICATORS ....................................... 33
5.1 FORCE FEEDING AND BEHAVIOURAL INDICATORS ................................................................................... 33
5.2 FORCE FEEDING, MANAGEMENT AND PAIN............................................................................................. 35
5.3 FORCE FEEDING AND PHYSIOLOGICAL INDICATORS ................................................................................ 35
5.4 FORCE FEEDING AND PATHOLOGY......................................................................................................... 38
5. 5CONCLUSION ....................................................................................................................................... 48
6 SOCIO-ECONOMIC ASPECTS OF IMPROVING THE WELFARE OF ANIMALS USED IN
THE "FOIE GRAS" INDUSTRY ..................................................................................................... 50
6.1 INTRODUCTION ................................................................................................................................... 50
6.2 THE FOIE GRAS INDUSTRY IN FRANCE ................................................................................................... 50
6.3 CONSEQUENCES IF THERE WAS NO CHANGE IN LEGISLATION OR PRACTICE ............................................... 52
6.4 SOCIO-ECONOMIC CONSEQUENCES IF FORCE FEEDING WAS BANNED ........................................................ 53
6.5 IMPROVEMENT OF MANAGEMENT FOR WELFARE REASONS AND THE ECONOMIC CONSEQUENCES ............... 55
7 RESEARCH ....................................................................................................................................... 57
7.1 ALTERNATIVE METHODS OF PRODUCTION ............................................................................................ 57
7.2 SUGGESTIONS FOR FUTURE RESEARCH.................................................................................................. 58
8 SUMMARY, CONCLUSION AND RECOMMENDATIONS ......................................................... 60
8.1 SUMMARY ........................................................................................................................................... 60
8.2 CONCLUSION ....................................................................................................................................... 65
8.3 RECOMMENDATIONS............................................................................................................................ 66
8.4 MINORITY OPINION - DR D.J. ALEXANDER ........................................................................................... 69
9 REFERENCES................................................................................................................................... 70
10 ACKNOWLEDGEMENTS ............................................................................................................... 88REQUEST FOR AN OPINION. The Scientific Committee on Animal Health and Animal Welfare is asked to report on the animal welfare aspects of the production of foie gras using ducks and geese.
INTRODUCTION
There is widespread belief that people have moral obligations to the animals with which they
interact, such that poor welfare should be minimised and very poor welfare avoided. It is
assumed that animals, including farm animals, can experience pain, fear and distress and that
welfare is poor when these occur. This has led to animal welfare being on the political agenda
of European countries.
Legislation varies, but E.U. member states have ratified the Council of Europe's Convention
on the Protection of Animal kept for Farming Purposes. Article 3 of that Convention states
that " Animals shall be housed and provided with food, water and care in a manner which,
having regard to their species and their degree of development, adaptation and domestication,
is appropriate to their physiological and ethological needs in accordance with established
experience and scientific knowledge” (Council of Europe, 1976).
In addition to political debate, the amount of information based on the scientific study of
animal welfare has increased. Scientists have added to knowledge of the physiological and
behavioural responses of animals and philosophers have developed ethical views on animal
welfare. Nevertheless, all agree that decisions about animal welfare should be based on good
scientific evidence (Duncan, 1981, Broom, 1988 b).
Scientific evidence regarding the welfare of ducks and geese in relation to foie gras production
is gathered together in this report. In chapter 1, different definitions of animal welfare are
presented, the four main indicators of animal welfare are discussed and the importance of
combining results from several indicators is emphasised. In the second chapter the extent of
production of foie gras is described and in the third, practical aspects of production are
summarised. Chapter four concerns the behaviour of geese and ducks in relation to force
feeding or “gavage”. The consequences for the birds of force feeding are described in chapter
five. The remaining chapters concern the likely socio-economic consequences of any changes
whose aim is to improve the welfare of the birds, suggestions for future research and
conclusions. Finally, there is a list of references quoted in the report.
11 WELFARE DEFINITIONS AND MEASUREMENT
1.1 Definitions of welfare
The terms " welfare " and " well-being " (Fraser, 1995, Hughes, 1989), are both used when
referring to the state of animal. In this report, the term " welfare " and not " well-being "will
be used. In discussions about animal welfare several definitions and descriptive statements
have been used. Some of the more commonly quoted include:
1. Brambell report (1965): "Welfare is a wide term that embraces both the physiological and
mental well-being of the animal. Any attempt to evaluate welfare, therefore, must take into
account the scientific evidence available concerning the feelings of animals that can be derived
from their structure and function and also from their behaviour".
2- Lorz (1973): "Living in harmony with the environment and with itself, both physically and
psychologically ".
3- Wiepkema (1982): " The inadequacy of the programmes performed to control relevant
aspects of the Umwelt, or the permanent failure of any behaviour, must cause severe feelings
of distress. In this period the animal really suffers and its well-being is at stake ".
4- Broom (1986, 1996): " The welfare of an individual is its state as regards its attempts to
cope with its environment ". "The origin of the concept is how well the individual is faring or
travelling through life. The state can be good or poor but, in either case, there will often be
feelings associated with the state, which we should try to measure, as well as using more
direct measures."
5- " Welfare is solely dependent on what animals feel ", (Duncan and Petherick, 1989).
6- " Welfare is mainly dependent on what animals feel " (Dawkins, 1990).
The first of these statements are rather descriptive. The second, referring to the animal being
in harmony with its environment, although commonly quoted is not very helpful in
scientifically assessing the welfare of animals under different conditions. Others refer to
adaptation to or control of the environment by the animal (3 and 4) and seem more
operational because they present opportunities for measurement. Some are specifically
concerned with the subjective experiences of the animal (5 and 6). However, there is general
2agreement amongst scientists about the overall meaning of the term welfare. The more effort
the animal is putting into coping, or the greater the biological cost of responding, the worse
the animal feels and the poorer its welfare. In most cases, the term welfare is used to cover a
continuum from very poor to very good welfare. When the animal is coping well there are
usually good feelings and welfare is good (Broom, 1996; Duncan, 1996; Moberg, 1996)
1.2 Assessment of Welfare
Before describing the health, production, physiological and ethological indicators of animal
welfare, it is necessary to give a general picture of why these indicators have been selected by
researchers. This is best achieved by outlining where they fit into the complex of interactions
between the animal and its environment. In the course of evolution every animal species has
adapted to an environment in which it is able to regulate its internal state and to survive and
reproduce. Regulatory systems in animals consist of the detection of changes in that
environment and responses to these changes which allow the animal to keep internal and
external conditions at an optimal level. In other words, the animal tries to control its
environment by using various coping mechanisms. Feelings play an important role in these
coping mechanisms, as do behavioural, physiological, biochemical and immunological
responses.
• 1.2.1 Health indicators
Health, which refers to the extent of any disease and injury, is an important part of welfare and
an important criterion in the assessment of the quality of life of animals. A range of the
measures which are used in welfare assessment are indicators of health. These include clinical
signs of disease and anatomical, physiological and immunological signs that the individual is
having difficulty in coping with its environment or is failing to cope. If some immunological
weakness or abnormality means that the individual would be more likely to succumb to
pathogen challenge, injury, etc. then the welfare is more at risk than in an animal which does
not have this weakness or abnormality. In the same way, inadequacies of physiological or
anatomical function, which have the same kinds of effects, are indicators of poor welfare. In
some cases, the poor welfare can be recognised by measurement in basal conditions, in others
3a challenge is needed to reveal it, and it is increased mortality or morbidity which indicates the
severe problem..
The term pathological is used for a body condition in which there are malfunctioning organs
or systems with clinical or subclinical effects.
A disease is by definition a pathological state where the causal factors are often clearly
identified and the clinical signs well defined. Pathogenic microorganisms and environmental
factors are the most common causal factors for disease, although genetic factors must not be
neglected. Environmental factors can precipitate the development of a disease process in the
absence of specific pathogens. Most diseases are usually accompanied by obvious clinical and
biochemical manifestations and the specific structural changes that affect a diseased organ can
be recognised at autopsy. There is a general consensus that such diseases lead to suffering.
However, not all diseases are always easy to recognise. A disease that develops in the absence
of well identified causal factors and lacks anatomopathological features is called a functional
disease (e.g. irritable bowel syndrome). Functional diseases are most often accompanied by
barely visible clinical signs, and cannot be readily diagnosed unless abnormal changes in the
affected physiological function are evidenced by appropriate clinical biochemistry methods.
Deviations from normality do not necessarily imply suffering. In addition, there are functional
diseases which occur without any evident biochemical abnormality but are accompanied by
painful symptoms. This is likely to be the case for functional gastrointestinal disorders. Many
functional diseases are reversible. It is not always easy to differentiate a functional disease
from the preclinical stage of a slowly progressing disease, specially in an organism in which
the duration of life is limited by the production process.
Injuries are painful when they occur in innervated bodily areas. In other parts of the body, they
can lead to deformations and deformities which can be unaesthetic but are not necessarily
painful. They may result in poor welfare in other ways. The occurrence of injury is an
indicator of the constraints exerted by the environment on the species specific behavioural
patterns of farm animals. Alterations in the skin and feathers do not necessarily compromise
physical health, at least on the short term, but indicate that the environment does not allow the
normal sequencing of body care activities.
4From an epidemiological perspective, health indicators of animal welfare must also be studied
with a broad population perspective, since frequently occurring problems must be considered
by society to be more alarming than rare events of the same problem. Especially for farm
animals, monitoring, recording, preventing and controlling disease take place routinely at the
herd and higher population levels.
In a group of animals, such as a flock, house, herd or any other population unit, the amount of
poor welfare caused by disease is a function of its incidence, severity and duration, as
described by Willeberg (1991).
This relationship has a number of important consequences for practical use and proper
interpretation of welfare-associated disease observations. The points relate to the source of
available data on disease occurrence, which in practice concentrate around: frequency of
treatment, mortality measures and frequency of lesions at slaughter.
Data on frequency of treatment for diseases are rarely consistently recorded by the farmer,
who most often carries out the treatment of flock animals. In some countries treatment data
do exist for dairy cattle, at least for treatments carried out by the veterinarian. In many field
trials of new production systems such treatment data are collected (Willeberg, 1993, 1997).
Measures which are indicators of the number of treatments are the amounts of drugs
purchased or used in the production, but such information is not often published nor otherwise
generally available, and it is also difficult to specify in which animals and for which conditions
they were used.
Data on mortality can be found, or are legally required, in some production systems. Mortality
data for regional or national populations may also be used to illustrate time trends in mortality
of farm animals (Agger and Willeberg, 1991). In assigning welfare importance to mortality
figures it is obvious that deaths are indicators of severe welfare problems, but information on
the causes of death as well as an estimate of the duration of the condition before death should
also be obtained in order to allow for a complete evaluation of a disease-associated welfare
problem.
5The frequency of lesions at slaughter is a prevalence estimate, not an incidence, and therefore
it is in itself a function of the duration of the condition. Furthermore, causes of chronic
conditions frequently seen at slaughter are often also determinants of the degree of pain
associated with the condition, e.g. a floor surface which gives rise to frequent foot-lesions
may also tend to magnify the pain of standing and moving in affected animals. However, there
may not be proportionality between the prevalence of lesions at slaughter and the magnitude
of the associated welfare problem which is particularly important in interpretations of
comparative studies of different production systems (Willeberg, 1991).
• 1.2.2 Production indicators
Under controlled conditions relative changes in the productivity of individuals may indicate
changes in welfare. A simple conclusion is that a sudden drop in productivity of an individual
from a high level to a low level probably indicates a welfare problem. If young animals are not
able to grow or if mature animals are unable to reproduce despite good opportunities to do so
then their welfare is poor. Hence these measures can be used to identify particularly poor
welfare. Welfare is also poor if a housing and management system results in a lower life
expectancy, in the absence of human interference, than that which would normally be expected
in such animals.
One of the main problems in using productivity as a measure of welfare is that, to the farmer,
productivity may mean the average production of a flock, the production per unit of food
intake, or the economic return per unit of capital or per unit of labour rather than the
productivity of the individual (Duncan and Dawkins, 1983). No economic measure should be
used when assessing welfare and, to be valid, assessment of production must be based on
measures from individual animals, not flocks. Comparisons between individuals may be
difficult because production is influenced by the strain and age of the bird, and can be
manipulated by management strategies, such as the lighting programme or the nutritional
content of the feed. A high level of production may even predispose the bird to production
diseases and so increase the risk of poor welfare. As with health, good production does not
necessarily indicate good welfare.
6• 1.2.3 Physiological Indicators
The most frequently measured physiological indicators are those associated with stress
responses, especially the activity of the hypothalamo-pituitary-adrenocortical (HPA) and the
sympathetic axis. In birds, this has typically involved measuring heart rate, glucocorticoid
concentrations, adrenal gland weight and responses to ACTH challenge.
However, as with the other measures, care must be taken in interpreting the results.
Physiological responses to short-term stressors may be different from responses to long-term
stressors because the system adapts when stress is prolonged. Furthermore, some of the
adrenal responses can be elicited by positive experiences such as excitement. It is therefore
too simplistic to equate an increase in adrenal activity with poorer welfare. Moberg (1996)
argues that instead of just measuring the adrenal response we should be measuring the
consequences of the stress, such as suppression of an immune response and failure to ovulate.
While there are difficulties in interpreting measurements of HPA activity, entering a
prepathological state clearly has an impact on the welfare of the animal.
Considerations when measurements of glucocorticoid levels in body fluids are made in order
to assess animal welfare are: 1. the duration of the response; 2. the extent of daily fluctuations
in normal adrenal cortex activity; 3. the variation in the magnitude of the response to different
kinds of problems. Some of these problems in interpretation of adrenal cortex responses are
discussed by Freeman (1985), Mason and Mendl (1993), Broom and Johnson (1993) and
Zulkifli and Siegel (1995).
In most domestic birds, when an animal is disturbed sufficiently by an event for an adrenal
cortex response to occur, the elevation of corticosterone in the blood takes at least two
minutes to become evident (Lagadic et al., 1990). It rises to a peak after around 15 minutes
and then decreases (quail: Launay, 1993; mulard duck: Noirault et al., in press). Hence the
effect of short term physical experience such as handling or transport (Remignon et al., 1996)
or psychological experience such as social disturbance or fear inducing stimulus (Siegel, 1982;
Mills et al., 1993; Launay, 1993) can be assessed readily by measuring the magnitude of
corticosterone increase in blood or other body fluids. During certain activities, such as e.g.
7courtship and mating, adrenal cortex activity may increase but this would not necessarily be
interpreted as indicating poor welfare.
When animals expect to be able to feed, or are frustrated because of absence of food,
increased adrenal cortex activity often occurs but during ingestion of food, adrenal activity
may well decline. Indeed, in situations where high levels of metabolism or general activity are
undesirable, for example when the ambient temperature is high, increases in glucocorticoid
production may not occur or may be actively suppressed (Broom and Johnson 1993). Such
effects are clearly adaptive.
In some circumstances animals show a greater response to ACTH after experiencing difficult
conditions over a long period. Other difficult conditions, however, do not elicit repeated
adrenal cortex activity and do not result in elevated cortisol production following ACTH
challenge (Ladewig and Smidt, 1989) If the conditions are prolonged and very severe in their
effects, adrenal function may be impaired and a reduced response to ACTH challenge may
result. Hence whilst an increased cortisol response to ACTH challenge indicates poor
welfare, the lack of such a response does not necessarily indicate that the conditions posed no
problem for the animal.
Endogenous diurnal fluctuations in glucocorticoid levels have to be taken into account when
assessing the effects of an experimental treatment (Ladewig 1989). Another factor that has to
be considered is that the plasma concentration of glucocorticoids is not only dependent upon
the rate of hormone secretion, but also upon its rate of clearance from the blood. Elevations of
glucocorticoids in response to different conditions at a particular time are seldom prolonged
for more than 30 to 60 minutes after that time. Hence single blood samples usually reveal little
about chronic problems and a sequence of samples must be taken at short intervals in order to
gain information about such problems. Also, the nature of the aversive stimulus may influence
the animal's reaction to it, including the extent of glucocorticoid secretion as a component of
that reaction (Mason and Mendl 1993). Increased glucocorticoid levels have been associated
with states of fear and anxiety, while pain does not always affect plasma glucocorticoid
concentration (Bateson, 1991). Prolonged pain can result in reduced plasma glucocorticoid
concentration (Lay et al,. 1992). Housing conditions may intermittently elicit adrenal cortex
8responses but random samples may miss these. Regular sampling of blood, using cannulated
animals gives more reliable information than infrequent measures of resting levels but due to
their small size and the constraint imposed by the canula this is rarely done in birds. Breed and
individual differences also exist in the activity of the adrenal cortex (Mills et al., 1993; Launay,
1993).
A final but most important point concerning the use of measurements of adrenal cortex
activity is that the sampling itself causes an adrenal cortex response. The sampling disturbance
effect will commence as soon as any approach to the animal is made in all but animals
thoroughly habituated to human proximity. However the response takes two minutes to be
evident and it has been shown that hens are not affected by the blood sampling of birds of the
same or neighbouring cages (Lagadic et al., 1990) .
As with corticosterone, heart rate is influenced by factors other than fear or anxiety. The level
of heart rate reflects the animal’s general metabolic demand, and is also influenced by
circadian rhythms. In order to avoid conflicting and equivocal results it is important to
distinguish between metabolic and emotional effects and to ensure that the measurement itself
does not cause much disturbance to the animal (Mills et al., 1985; Broom and Johnson, 1993).
Heart rate changes provide useful information about the effects of short term problems on the
animal, but the measure gives little information about the long term effects. It is necessary to
complement measurements of heart rate with other indices such as those pertaining to
behavioural activity. An alternative to heart rate is the measurement of shank temperature
which drops during the vasoconstriction following adrenal secretion.
All the cited measures are of short term (minutes to hours) stress reactions. In birds
calculation of the heterophil/ lymphocyte ratio allows some measurement of longer term
(hours to weeks) stress (Gross and Siegel, 1983 ; Mills et al., 1993).
• 1.2.4 Ethological Indicators
The advantages of ethological indicators, that are studies of animal behaviour, are that they
are non-invasive and changes may precede those of other indicators. Ethological studies are
9of three main types.
a) In the first type, birds are placed in the environment under investigation and their behaviour
is compared with that of birds either under feral conditions or in an environment assumed to
be ideal. This approach is useful because it shows which behaviours are changed by the
environment or treatment under investigation, so that further scientific study of these can be
carried out. It also provides information about how birds choose to allocate resources in
good conditions. However the problem with this approach is that it is not immediately
obvious whether a particular behaviour, or change in behaviour, is an indication of regulatory
disturbance or failure, or whether it is an appropriate adaptation to a change in environment.
When the behaviour patterns have obvious detrimental effects, as is the case for feather
pecking (Blokhuis, 1989), the interpretation of results is easy, but in other cases it is not. For
example, Fölsch (1980) found differences in locomotion and acoustic behaviour of hens
placed in different environments. But to use such parameters to demonstrate poor welfare, it
must first be shown that these changes indicate frustration or some other problem.
b) The second method is to give birds access to more than one environment, resource, or
opportunity for behaviour and assume that they will choose that which is in their best interest
(Hughes and Black, 1973; Dawkins, 1976; Rutter and Duncan, 1991; 1992). Closely related
to these choice experiments are operant conditioning techniques in which birds have to work
to obtain, or to avoid, some aspect of their environment (Dawkins, 1983; Meunier-Salaun and
Faure, 1985; Lagadic, 1992 ). Also, demand functions can be generated by making animals
perform a variable amount of work in order to obtain the same amount of reward (Dawkins,
1983; Ladewig and Mathews, 1996). In all of such studies, the strength of preference should
be assessed.
Poorly designed preference tests have been criticised by Duncan (1978) and operant
conditioning is considered by Dawkins and Beardsley (1986) to be a problematic way of
measuring animal motivation. However, others consider these to be the most powerful tools
available for studying the needs of animals, to show certain behaviour or to obtain certain
resources even if some caution should be taken in the interpretation of results (van Rooijen,
1982, Ladewig and Matthews, 1996).
10c) The third type of ethological method used to assess welfare is to observe behaviour in
experimental situations and compare their behaviour with the behaviour in the environment
under study. In a situation where the animals do not appear to be coping, or cope only with
great difficulty, several behavioural changes may be apparent, some of which may be called
abnormal or stereotypic (Wiepkema, 1985). Although there is some controversy about the
exact meaning of stereotypies (Dantzer and Mormède, 1981; Wiepkema, 1987; Savory, 1989;
Cooper and Nicol, 1991; Mason, 1991), it is generally thought that suffering occurs before
stereotypies are established and animals showing stereotypies are having difficulty in coping so
their welfare is poor.
When birds are fearful, they may show retreat, avoidance behaviour or freezing behaviour as
well as physiological responses. Stereotypies shown by birds including: head-shaking (Levy,
1944) the plucking and carrying of their own feathers (Hinde, 1958), route tracing (Keiper,
1970), pacing (Duncan, 1970) and spot-pecking (Staddon and Simmelhag, 1971).
The apparent simplicity of ethological studies can lead to them being misused. However, as
with physiological indicators, when used appropriately ethological indicators can be a sensitive
measure of animal welfare.
1.3 Combining Results from different indicators
When faced with one kind of difficulty, an individual may show a measurable response, such
as increased adrenal activity, but other kinds of difficulty may elicit no adrenal change at all.
Similarly, increased levels of abnormal activity, an overall reduction in responsiveness, a fever
response, an increased T-cell activity, a loss of detoxification ability or a suppression of
growth may occur in response to one problem but not in response to another. Hence it is
agreed that there is no single indicator of animal welfare and that to get the best assessment,
several different measurements have to be taken (Broom, 1986; Broom and Johnson, 1993).
In some cases, all indicators, be they health, production, physiological or ethological, point in
the same direction and the interpretation is clear. On other occasions there are conflicting
11results (Mason and Mendl, 1993). In each case a balanced overall assessment of welfare must
be made.
Another problem in the evaluation of animal welfare is the lack of knowledge of how animals
experience, for example, the states of disease, conflict or frustration. Are some states more
important from a welfare point of view than the others? These questions are difficult to
answer with our present knowledge of veterinary and ethological science. An alternative view,
therefore, is that of Fraser (1995) who proposed that instead of attempting to "measure"
animal welfare, the role of science should be to rectify and prevent all welfare problems.
Rushen and de Passillé (1992) acknowledged the problems in measuring welfare and proposed
that criteria for assessing welfare can be divided into design criteria, which specify what must
be included in an animal's environment to promote good welfare e. g. space allocations etc.,
and performance criteria, which indicate what parameters of the state of an animal indicate
good or poor welfare e.g. production performance, physiological indicators of stress etc. They
propose that housing can be assessed using an optimum mix of these two criteria.
1.4 Summary
Despite there being several definitions of animal welfare, scientists agree on many of the basic
principles. For example, many agree that welfare particularly concerns what an individual
animal feels, but think that the techniques to measure feelings are not very well developed at
the present time. Techniques to measure the effort an animal is putting into coping with a
situation are better developed and, since this should be correlated with feelings, it is argued
that current research should concentrate on these measures as indicators of welfare. The most
commonly used welfare indicators are measures of health, production, physiology and
behaviour. Any one of these indicators may be used on its own to indicate poor welfare, but
an integrated (Smidt, 1983) or holistic (Simonsen, 1996) approach gives a better indication of
the effort the animal is putting into coping and hence the biological cost to the animal of
responding. With regard to assessing housing for animals, recent thinking supports a balance
between design and performance criteria and focusing on specific welfare problems. Hence
12the welfare of ducks and geese in relation to the housing and the procedures which are used
during force feeding can be assessed.
132 THE ORIGINS AND DISTRIBUTION OF FOIE GRAS PRODUCTION
2.1 The products
The “foie gras” (or “fat liver”) products derived from the force feeding of ducks and geese are
defined by the following European and French regulations.
Regulation Nf 1538/91 of the commission dated the 5th of June 1991 (JO N°L 143, 7th of
June, P. 11; JO N°L233, 22nd of August 1991, p. 31) defines norms for the characteristics of
the products of different birds. In particular force fed ducks and geese are defined by the
minimal weights of their livers, 300g for ducks and 400g for the geese.
A French regulation (Décret N° 93-999 du 9 Août 1993 relatif aux préparations à base de foie
gras) defines the different types of products prepared with foie gras. All these preparations
involve some percentage of fat liver (from 100% to 20%). Another text, “Arrété du 8 avril
1994 relatif aux méthodes officielles d'analyse des préparations à base de foie gras”,
complements the first one by describing methods for the analysis of the different
“ préparations“. Methods for determining the percentage of fat liver and the size of the pieces
of the liver are given. A histological analysis is also described and the text defines as not
acceptable products where the hepatocytes do not include fat globules, a high proportion of
perivascular tissue, tissues other than fat liver from ducks and geese and a high proportion of
tissue with lesions.
The different products are described as follows:
1 - “foie gras entier” (whole fat liver) the liver is sold as a whole,
2 - “foie gras” parts of liver are used but the livers do not have to be in one piece,
3 - “ bloc de foie gras” only fat livers are used but they are processed by mechanical devices
and chunks of liver are not visible,
4 - “parfait de foie” includes at least 75% of fat liver processed by mechanical devices,
145 - “médaillon de foie” and “pâté de foie” product with at least 50% of fat liver. This fat liver
is in chunks or is mechanically prepared and is clearly set in the centre of the preparation with
products from other origins on the outside.
6 – “galantine de foie” product with 50% of fat liver mixed with stuffing.
7 – “mousse de foie “ product with 50% of fat liver mixed with stuffing and presented as a
“ mousse”.
8- “produits au foie gras” products with foie gras which contains at least 20% of fat liver
Other products exist which include livers from non force fed ducks and geese, in particular
“pâté” and “mousse”.
A new nomenclature for those products was defined at the European level and published in
1995 (nomenclature PRODCOM). The changes in this production are thus difficult to
determine on a long term basis. However the general trend is of an increase of production in
France during the last fifteen years (from 5900T in 1990 to 10670T in 1996; CIFOG, 1996)
and a decrease in imports to France (from 2620T in 1990 to 1800T in 1996). The quantity
processed by the industry increased from 4450T in 1990 to more than 6700T in 1996. The
other part of the production is processed and some is sold directly at the farm level.
In 1996, 6200T of 100% foie gras products (products 1 to 3) and 700T of the other foie gras
products (products 4 to 8) were sold by the food industry at prices of around 225FF/Kg and
155FF/Kg. 13000T of non foie gras “pâté and mousse” were produced in 1996 at a mean
price of approximately 32F/Kg. These differences in prices are related also to the differences
in the timing of the consumption. Foie gras products are sold usually towards the end of the
year whilst «pâté de foie de volaille » is sold all year round. On average, each family in France
buys foie gras products for 140FF on 1.7 occasions and “mousse ” and “pâté” for 37FF in 2.5
occasions every year.
2.2 Origins and species
Some geese have been reared since ancient times in such a way that an especially fatty liver
could be obtained from them. There is reference to this practice in the satires by Horace
15(Book ii, Chapter pIII) and in the statuette of a fattened goose more than 4500 years old from
the Ancient Egyptian Empire exhibited at the Louvre. Other authors such as Herodotus and
Homer have also described practices corresponding to force feeding in their works (Carrère,
1988). The feeding of geese according to the method carried out in Gascogne, south-west of
France was described as early as 1619 by Olivier de Serres, "et jecur anseris albae pastum
ficis pinguibus" the translation of which is "and the liver of a white goose fattened with oily
figs".
The fat liver, internationally called “foie gras”, was produced traditionally from geese.
However in recent years there has been a widespread change to the use of ducks rather than
geese, mainly for financial reasons. The change in France has been dramatic from an
exclusively goose production in the 1950s to a current production of liver, 94% (9700 tonnes
of foie gras) of which is from ducks and only 6% (600 tonnes) from geese.
The duck chosen for foie gras production is a hybrid between the muscovy duck (Cairina
moschata) and the domestic duck (Anas platyrhynchos). There is an important sexual
dimorphism in muscovy ducks, the adult male weighs between 4.5 and 5 kg while the adult
female weighs between 2.2 and 3 kg. Farmers reported that during force feeding, these
animals were too nervous and at the end of the force feeding period, their fatty liver had a
tendency to lose fat by melting. For all these reasons, these animals were crossed with
domestic ducks. A male muscovy duck is crossed with a female of a breed such as the Pekin
duck. The product is a sterile hybrid, the so-called mulard duck. The males are used for foie
gras production and the females are raised for meat consumption.
Geese (Anser anser) which are kept for force feeding are of specific strains: oie du Gers and
oie grise du sud-ouest. These strains are selected because of the capacity of the animals to
produce fatty livers.
2.3 Production in France
In France, by tradition, force feeding was mainly carried out in Alsace and in the south west of
the country, including Aquitaine and Midi-Pyrénées areas. These areas still provide 80% of
16the total production. In the last 10 years, foie gras production has developed in a second area
in the western part of the country (Pays de Loire and Bretagne) where the production
represents nowadays 18% of the total French production. Some force feeding is currently
practised in all geographical regions.
After a considerable increase in production over ten years, production levels have begun to
stabilise with an increase of 7% between 1994 and 1995. In 1995, the French production of
10385 tonnes was supplemented by 2850 tonnes of imported foie gras, which is a decrease of
17% from the 1994 level, (CIFOG 1996). In order to obtain this production in France,
789,000 geese and 18,395,000 ducks were bred and force fed in 1995. The number of ducks
kept for this purpose showed an increase of 7.6% between 1994 and 1995 but there was no
increase between 1991 and 1995 in the number of geese kept.
In 1995, 342 tonnes of foie gras, as a raw product were exported and 12 893 tonnes were
used in France. Of this 6 394 tonnes were transformed by food industries and 6 499 tonnes
were used in restaurants or for private consumption. 380 tonnes of processed foie gras were
exported in 1995 in particular to: Switzerland (73 tonnes), Belgium and Luxembourg (64
tonnes), Spain (43 tonnes). United-Kingdom (37 tonnes), Germany (32 tonnes), Japan (27
tonnes) and Netherlands (22 tonnes).
Meat production which is associated with the production of foie gras is estimated as nearly
28,000 tonnes. This corresponds to 10,000 tonnes of fillets (magrets), 10,000 tons of thighs
(so called " cuisses à rotir ou à confire "), 4,500 tonnes of " manchons ", 1,200 tonnes of "
aiguillettes ", 1,500 tonnes of gizzards and 450 tonnes of hearts.
2.4 Production in Belgium
The annual production was estimated as 40 tonnes in 1993. It had increased to 48 tonnes in
1995. The number of animals involved in this production was 98 000 ducks in 1995 (90 000 in
1993) and 2 000 geese in 1995 (same number in 1993). The annual consumption is of 200
tonnes.
172.5 Production in Spain
The annual production was estimated as 34 000 animals in 1990. It gradually increased to an
average of 45 000 animals in 1995 and an estimated 55 000 animals in 1996.
183 THE PRACTICE OF REARING AND FORCE FEEDING
3.1 Management before the force feeding period
After hatching, the mulard ducks are kept in a building on straw for 4 weeks. They are then
allowed to live outside, on grass for some weeks.
In contrast to certain other species, there is no crop in the goose and in the duck but the
oesophagus can become dilated. The preparation of the animal is carried out in order to
emphasise this dilation. Prior to force feeding, the bird is prepared for the various
manipulations in two phases. In phase one from the third week onwards, the bird is subjected
to training that is designed to dilate the oesophagus. This is achieved by grass ingestion for
example. Such preparation makes it possible for the bird to receive a large quantity of food
very rapidly, which will occur during the force feeding period.
In phase two, the bird is subjected to a period of rapid muscle growth (Bénard, 1992). During
this period, which generally lasts about four weeks, the bird receives a large quantity of food
which is fed ad libitum. This results in oesophagus dilation and progressively leads to the half-
fatted state. The ration is distributed as a mash and is at this stage usually composed of maize
20%, wheat 53%, soya cake 19%, mineral and vitamin supplement 8%. In this diet, the
metabolisable energy is around 680J. The composition is as follows: proteins 16.5%, starch
47.9%, cellulose 2.7%, fat 2.1%, lysine 0.78%, methionine 0.37%, tryptophan 0.20%,
phosphorus 0.72%, calcium 1.16%, chloride 0.20%, sodium 0.16%. The dry matter is around
87.5% and ash is 6.3%. This diet is provided when the birds come in from the field. The
periods when the birds are allowed to go out are then progressively reduced so as to condition
them to the restraint associated with the force feeding period.
3.2 Management during the force feeding period.
During this period there is forced daily ingestion, for 12 to 15 days for ducks and 15 to 18
even 21 days for geese, of a large amount of energy-rich food, with a high carbohydrate and
fat content and an uneven amino acid balance: lysine 0.28%, methionine 0.22%, tryptophan
190.07%, leucine 1.28%, arginine 0.49% (Larbier and Leclercq, 1992). Animals receive two
meals per day (ducks) or three meals per day (geese).
The basic feed is maize which is usually boiled and mixed with fat principally to facilitate
ingestion. It is administered by force using a funnel fitted with a long tube consisting of an
auger or pneumatic system that forces the maize into the oesophagus. The amount is fixed so
as to ensure that the crop-like area is full. Efforts are made to avoid any tearing or splitting of
the oesophagus by the movements of the tube or the amount of food inserted.
Various parameters are of fundamental importance during this period. Water must be
continuously available. Many farmers make the water alkaline by adding sodium bicarbonate.
The maize used is at least one year old so that the starch is more easily assimilated. Some
authors have shown that, based on the increase in body weight and liver weight, the
administration of grain maize is preferable to that of a fluid paste obtained by grinding the
maize in water. This may be explained by better assimilation of the starch, due to the slowing
down of grain transit. Finally the addition of lactic ferments limits the multiplication of
enterococci, and thus the risks of enteritis associated with poor digestion (Bénard, 1992).
To deliver the food, an auger (endless screw) is generally used. The auger is contained within
the feeding tube. It is moved either by hand in traditional units or with an electric motor. With
such systems, used for 30% of the birds, it takes between 45 and 60 seconds to deliver the
meal. In larger units, pneumatic devices are used. They allow the farm worker to deliver the
same quantity of food in 2-3 seconds. Such a system is connected through a computer which
helps to determine the amount of food to deliver to each bird on the basis of the body weight
and the amount of food which was delivered during the preceding meals.
Whether force feeding is to be carried out using an auger or using a pneumatic device, the bird
must first be restrained and positioned by a person. In order to make catching the bird easier,
the ducks or geese are either kept in groups in a small pen or cage or in a wire or plastic cage
holding only one bird. Most ducks are now kept in cages of a size which does not allow the
bird to turn around or stretch its wings. The head protrudes through a hole in the front of the
cage roof. 20% of the ducks and all of the geese are kept in groups.
20The person who will commence the force feeding grabs the neck of the bird, retrains the wings
if the bird is in a pen, draws the bird towards the feeding pipe, thrusts the 20-30 cm long pipe
down the throat of the bird and initiates the food pumping procedure. When food delivery is
completed, the pipe is removed. The insertion and removal of the pipe must be carried out
carefully in order to avoid injury to the oropharynx or oesophagus of the bird and potential
mortality.
In some farms the ducks or geese are kept in near darkness for all of the time except the
feeding period during the 2-3 weeks of force feeding.
3.3 Housing of ducks and geese during the force feeding period.
Three types of rearing systems are used for ducks and geese during the force feeding period
(Table 1):
Table 1 Some characteristics of the 3 types of housing systems used for force feeding ducks
and geese
Frequency (%) Group size Surface Surface per bird (cm²)
(cm²)
Ducks Geese Ducks Geese Ducks Geese
Individual 80 1 900- 900-1050
cage 1050
Group 0.5 50 4-5 3 10000 2000-2500 3300
cage
Pen 19.5 50 12-15 9 30000 2000-2500 3300
- Individual cages: These cages are made of wire mesh or plastic and are always of the flat-
deck type. The size is 20 to 21 cm wide, 45 to 50 cm long and 27 to 33 cm high. The front
and top of the cage are open to allow the duck to drink and to be force fed. Water is provided
21in a trough in front of the cage. The top and most of the time the front wall as well make the
door of the cage (Figure 1).
Figure 1. Schematic view of a cage
The basic type has a rectangular section but a lot of different shapes can be found (Figure 2)
and in some of them the lateral walls are partly open to allow more space for the feet.
Figure 2: Longitudinal sections of various cages
22Figure 3 Transverse sections of various cages
The floor was originally flat but is now often either open or of a trough shape at the level of
the breast in order to reduce breast blister incidence (Figure 3).
- Group cages: They are made of wire and have a flat wire mesh floor. They are usually
square and measure 1 x 1 m in surface. The wire mesh walls are about 80 cm high and the
front of the cage is made of bars to allow access to the water trough placed in front of the
cage. They have no roof and a system permits the restraint of one animal at a time during the
force feeding act.
- Pens: Pens are usually 3 m² (1 x 3 m) and are made of wire mesh walls and slatted floor.
Water is available from a trough placed in the pen.
234 NORMAL BEHAVIOUR AND OTHER FUNCTIONING OF GEESE AND DUCKS
RELEVANT TO FORCE FEEDING
4.1 The natural behaviour of geese, muscovy ducks, domestic ducks and their hybrids
Traditionally, "foie gras" has been produced by domestic geese. Today, by far the most
common type of bird used for the purpose of "gavage" is the male hybrid between the
muscovy ducks and domestic ducks. In the following, an account is given for the natural
behaviour and ecology of these animals.
The ancestor of most modern geese is the greylag goose (Anser anser) (Clutton-Brock,
1981). It was domesticated probably more than 7,000 years ago (Clutton-Brock, 1981).
Nevertheless, the basic behaviour patterns of the greylag goose have not been altered
substantially, just as in other domesticated species, as revealed by different behaviour studies
(Lorenz, 1950; Lorenz, 1972; Kretchmer and Fox, 1975; Bellrose, 1980; Clutton-Brock,
1981). Greylag geese are widely spread over the northern hemisphere where they occupy
living areas in close connection with water. Most of their time is spent in water, but they move
and forage extensively on land (Lorenz, 1972; Bellrose, 1980). They forage both on land, by
grazing, and in water, by eating aquatic plants; also insects, molluscs and other animals form
part of the diet. Most of the daytime is spent in search for food (Lorenz, 1972; Bellrose,
1980). Geese form pairs which usually stay together throughout life (Lorenz, 1950; Lorenz,
1972; Bellrose, 1980). The nests are built on the ground, usually close to the water, and the
eggs are incubated by the females alone, whereas both sexes share the parental care once the
young have hatched (Lorenz, 1950; Lorenz, 1972; Bellrose, 1980). Many greylag geese
migrate extensive distances from the northern breeding grounds to southern winter areas,
which in Europe range from central to southern parts of the continent (Bellrose, 1980).
The muscovy duck (Cairina moschata) belongs to Cairini, hence it is quite distantly related to
the origin of the domestic ducks, the mallard (Anas platyrhynchos), which belongs to the
Anatini, both subgroups within the family Anatidae (Leopold, 1959; Bellrose, 1980). The
sexual dimorphism in size of the muscovy duck is considerable, the male being almost twice as
big as the female which is not the case in mallards; however mallards have a pronounced
24plumage dimorphism which is not the case in muscovies. There are also some striking
differences between the behaviour of the two species. The muscovy duck in the wild lives in
Central and South America, where the climate is subtropical to tropical, and they are not
migratory (Hoffman, 1992a). They are omnivorous and eat both animal- and plant-based
nutrients, such as small fish, insects, molluscs, small reptiles, worms, algae and terrestrial
plants (Brauer, 1991). Muscovy ducks are mostly active at dawn and dusk, when most of their
time is used for foraging, whereas the middle of the days and the nights are usually spent on
branches in trees close to water (Leopold, 1959). They have a promiscuous mating system and
copulation takes place in water during the mating season which coincides with the rainy
season (Breuer, 1991). Nest sites are selected by females alone, and the nests are mostly built
in hollows in trees, but also sometimes on the ground. The clutches consist of 8-15 eggs
which are only incubated by the female. The female is also solely responsible for caring for the
young until they can fly (Leopold, 1959). Muscovy ducks were domesticated by native
peoples in South America, but the date of the domestication is not known (Breuer, 1991). In
the 16th century they were introduced to Europe and are today kept and farmed in large parts
of the world. The behaviour of the domesticated breed is quite similar to that of the wild form
(Breuer, 1991). Whereas most pure muscovy ducks are kept for meat production, the species
is also important for production of fat liver, but in the form of hybrids with domestic ducks.
Domestic ducks originate from the mallard, the most abundant and widely spread duck in
Northern Hemisphere (Bellrose, 1980; Clutton-Brock, 1981). Mallard may be largely
sedentary in a small area or may range over some hundreds or even thousands of kilometres in
search of feeding areas. Food choice is similar to that of muscovies (Bellrose, 1980). Unlike
muscovies, mallards form pairs for a part of the year. However, the incubation and caring for
the young is done completely by the female and the male usually leaves during the incubation
period (Lebret, 1961). Nests are built on the ground and mallards are dependent on water and
not inclined to go into trees (Bellrose, 1980). Domestic ducks have retained the behaviour of
their ancestors, although thresholds for release of certain behaviour patterns such as
aggression has been altered (Desforges and Wood-Gush, 1975 a and b, 1976.)
With respect to the social behaviour, both mallards and greylag geese live in pairs during the
reproductive season, or on their own together with the offspring. However, before and during
25migration, large numbers of birds usually aggregate for foraging, resting and migrating
(Bellrose, 1980; Breuer, 1991). Both species have a rich repertoire of social behaviour,
comprising both visual displays and acoustic signals (Lorenz, 1972). Muscovy ducks spend a
large part of their time in groups, both during daily activity and during night rest (Leopold,
1959). Hence, all three species may be considered as basically social animals to their nature.
The hybrid used for force feeding, obtained by crossing a male muscovy and a female
domestic duck, or mulard, is sterile and shows a number of anatomical features from each
species; for example, sexual dimorphism in size and coloration is almost absent, eggs hatch
after an intermediate time of incubation (32 days in hybrids, 28 in domestic ducks and 35 in
muscovies), the birds have claws like muscovies, but very rarely go into trees, like domestic
ducks (Hoffman, 1992b). Hoffman (1992a) concludes that the general behaviour of the
mulard appears to be most similar to that of muscovies, with the exception that they moved
more slowly and spent more time in water, traits that are more similar to domestic ducks.
Hoffman (1992b) also reported that mulards do not fly.
4.2 Occasions for Food Storage in Birds
Animals which migrate or hibernate are adapted to store food which can be made available
later. For example the mean weight of the blackpoll warbler Dendroica striata increases from
10-12g to 20-23g before migration to the breeding grounds. In some birds this increase in
weight is, in part, a consequence of fat accumulation in the liver but in other birds there is fat
accumulation elsewhere in the body. Animals which feed irregularly in wild conditions are also
often adapted to store food when a large meal is taken. It may be that such mechanisms are
exploited when ducks and geese are given a large volume of food which results in a substantial
expansion in the size of their liver. The greylag Anser anser is often migratory and may travel
long distances during migration. Some wild mallard Anas platyrhynchos are sedentary but
others migrate in some circumstances. However, the muscovy duck Cairina moschata is a
tropical species which is not migratory. Hence whilst the domestic goose might well be
adapted to store food before migration, it is less likely that a cross between the domestic duck
and the Muscovy duck, the Mulard, has such a potential for food. These hybrids do
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